This invention relates to an adjustable anchorage, and relates more particularly but not exclusively to an anchorage for a safety net to be utilised during the construction of a building, the net requiring to be reliably anchored to the lower flanges of I-beams forming the skeleton of the building being constructed.
It is currently common for buildings, particularly larger commercial premises, to be constructed around a three-dimensional skeleton or framework of steel I-beams which serve to support concrete flooring slabs or metal deck flooring. Most of the framework is usually at a considerable height above ground, and consequently falls present a grave risk of death or injury to construction workers. The injury risk from falls is mitigated by the use of a safety net suspended from the I-beams around the edge of a floor level or other work location in the building. In the United Kingdom, parts 1 and 2 of BS EN 1263 govern such safety nets and their deployment. Part 2 of BS EN 1263 directs that safety nets be attached to horizontal beams by passing a securing rope alternately through the edge of the net and around the beam. While such an attachment procedure can securely anchor the net (if diligently carried out), the procedure presents certain problems, including the substantial time required to reeve the rope many times through the net edges and around the beams, converse difficulties in removing the rope to free the net (aggravated by weathering of the rope) and the loss of fall protection due to the need to remove the rope (and net) for the laying of flooring supported on the top edges of the beams.
It is an object of the invention to provide an adjustable anchorage which is capable, inter alia, of being applied to reversibly anchoring a safety net to a horizontal I-beam or similar article in a rapid and simple manner without impeding access to the upper surface of the I-beam during such use of the anchorage. (It is to be understood that in this specification and its accompanying claims, use of the term xe2x80x9cI-beamxe2x80x9d not only encompasses beams whose transverse cross-section resembles an xe2x80x9cIxe2x80x9d with bilateral flanges on the top and bottom edges of its central web, but also encompasses beams having other cross-sections though always with bilateral flanges (or their mechanical equivalent) along or near the lower edge of such other forms of beam). It is a further object of the invention to provide an adjustable anchorage capable, inter alia, of being adjusted for efficient utilisation on I-beams whose lower edge bilateral flanges have respective widths in a wide range of widths
According to a first aspect of the invention there is provided an adjustable anchorage comprising first and second hook means each capable of being hooked around a respective opposite edge of a bilateral flange, attachment means on at least one of said first and second hook means for the attachment of an article thereto, and adjustable linking means extending between said first and second hook means for mutually linking said first and second hook means in use of said anchorage with said first and second hook means each hooked around a respective opposite edge of the bilateral flange and for thereupon retaining said first and second hook means against the respective opposite edges of the bilateral flange, with the adjustability of said adjustable linking means allowing effective use of the anchorage on various bilateral flanges having respective widths in a substantial range of widths.
Said adjustable linking means preferably has an adjustable length between said first and second hook means. Said adjustable linking means may comprise a strap or web secured at one end thereof to one of said first and second hook means together with clamp means for clamping the strap or web to the other of said first and second hook means at a selected location along the strap or web displaced from said one end of the strap or web. Said adjustable linking means preferably incorporates tensioning means capable of applying tension between said first and second hook means whereby to force said first and second hook means against the respective opposite edges of the bilateral flange in use of the anchorage, and said tensioning means may comprise an overcentre form of said clamp means tending in use to shorten the strap or web between said one end thereof and said selected location thereon. Said adjustable linking means may alternatively comprise mutually interpenetrating tongue and slot means together with latch means functioning to latch the tongue and slot means together at a mutual interpenetration which places the first and second hook means at a selected mutual separation.